RE: Thunder Tiger 75 Four Stroke?
Drilling a passage is easier said than done. First, try to find a small drill long enough to reach the area you are trying to drill!! Removing the bearing seal is the easy solution. While you have the crankcase hot to remove the main bearing if you are worried about a wet nose, just replace the front bearing with a sealed unit.
The 30% oil is a mistake. The regular 18% is just fine.